class classname(object):
    def __init__(self):
        self.new_urls=set()

        self.old_urls=set()

    def has_new_url(self):

        pass

    def get_new_url(self):
        pass

    def add_new_url(self):
        pass

    def  new_url_size(self):
        pass
    
    def old_url_size(self):
        pass

        
